The dhcp server only worked, when I added a sleep 10 in /etc/init.d/isc-dhcp-server. It seems that the dhcp server doesn’t start as long as “wlan0” isn’t completely initialized. For my BeagleBone waiting 10s worked.

I would however like to learn how to do this properly (let the dhcp server wait until “wlan0” is up and than start the demon).